Comparison between conventional colectomy and complete mesocolic excision for colon cancer: a systematic review and pooled analysis : A review of CME versus conventional colectomies

Impact of imaging magnification on colorectal surgery: a matched analysis of a single tertiary center

BACKGROUND

Laparoscopy has been increasingly applied in colorectal surgery, and imaging systems have been improving concurrently. The present study aims to compare outcomes following colorectal surgery with the 4K and traditional high-definition (HD) video systems.

METHODS

All consecutive patients undergoing laparoscopic colorectal surgery between April 2016 and June 2020 were retrospectively retrieved from a prospective institutional database. The study population was matched according to the imaging system (4K versus HD groups) through a propensity score matching (PSM) based on perioperative characteristics of 15 patients. A stratified analysis according to surgical procedures (right, left colectomy, and low anterior resection) was also performed. Primary endpoints were intraoperative blood loss and perioperative transfusions. Also, intra- and postoperative morbidity, operative time, lymph node harvest, and length of hospital stay (LOS) were investigated as secondary outcomes.

RESULTS

After PSM, 225 patients were included in both 4K and HD groups. The intraoperative blood loss was significantly lower in the 4K group (p = 0.008), although no different volumes of blood transfusion were required. Postoperative complications presented in similar proportions, while significantly higher rates of abdominal collection (p = 0.045), reoperation (p = 0.005), and postoperative urinary disorders occurred in the HD group. After stratification, the right colectomy subgroup shared similar associations with the study population. LOS did not change between groups, although readmissions were significantly lower in the 4K group (p < 0.001).

CONCLUSIONS

The 4K imaging system represents a technological advance providing better surgical outcomes, such as the minimization of intraoperative blood loss and postoperative morbidity.

Macroscopic Evaluation of Colon Cancer Resection Specimens

Colon cancer is a common disease internationally. Outcomes have not improved to the same degree as in rectal cancer, where the focus on total mesorectal excision and pathological feedback has significantly contributed to improved survival and reduced local recurrence. Colon cancer surgery shows significant variation around the world, with differences in mesocolic integrity, height of the vascular ligation and length of the bowel resected. This leads to variation in well-recognised quality measures like lymph node yield. Pathologists are able to assess all of these variables and are ideally placed to provide feedback to surgeons and the wider multidisciplinary team to improve surgical quality over time. With a move towards complete mesocolic excision with central vascular ligation to remove the primary tumour and all mechanisms of spread within an intact package, pathological feedback will be central to improving outcomes for patients with operable colon cancer. This review focusses on the key quality measures and the evidence that underpins them.

Simultaneous, Multi-Channel, Near-Infrared Fluorescence Visualization of Mesenteric Lymph Nodes Using Indocyanine Green and Methylene Blue: A Demonstration in a Porcine Model

Near-infrared fluorescence (NIRF) image-guided surgery is a useful tool that can help reduce perioperative complications and improve tissue recognition. Indocyanine green (ICG) dye is the most frequently used in clinical studies. ICG NIRF imaging has been used for lymph node identification. However, there are still many challenges in lymph node identification by ICG. There is increasing evidence that methylene blue (MB), another clinically applicable fluorescent dye, can also be useful in the intraoperative fluorescence-guided identification of structures and tissues. We hypothesized that MB NIRF imaging could be used for lymph node identification. The aim of this study was to evaluate the feasibility of intraoperative lymph node fluorescence detection using intravenously (IV) administered MB and compare it to ICG via a camera that has two dedicated near-infrared (NIR) channels. Three pigs were used in this study. ICG (0.2 mg/kg) was administered via a peripheral venous catheter followed by immediate administration of MB (0.25 mg/kg). NIRF images were acquired as video recordings at different time points (every 10 min) over an hour using the QUEST SPECTRUM^® 3 system (Quest Medical Imaging, Middenmeer, The Netherlands), which has two dedicated NIR channels for simultaneous intraoperative fluorescence guidance. The 800 nm channel was used to capture ICG fluorescence and the 700 nm channel was used for MB. The target (lymph nodes and small bowel) and the background (vessels-free field of the mesentery) were highlighted as the regions of interest (ROIs), and corresponding fluorescence intensities (FI) from these ROIs were measured. The target-to-background ratio (TBR) was then computed as the mean FI of the target minus the mean FI of the background divided by the mean FI of the background. In all included animals, a clear identification of lymph nodes was achieved at all time points. The mean TBR of ICG in lymph nodes and small bowel was 4.57 ± 1.00 and 4.37 ± 1.70, respectively for the overall experimental time. Regarding MB, the mean TBR in lymph nodes and small bowel was 4.60 ± 0.92 and 3.27 ± 0.62, respectively. The Mann-Whitney U test of the lymph node TBR/small bowel TBR showed that the TBR ratio of MB was statistically significantly higher than ICG. The fluorescence optical imaging technology used allows for double-wavelength assessment. This feasibility study proves that lymph nodes can be discriminated using two different fluorophores (MB and ICG) with different wavelengths. The results suggest that MB has a promising potential to be used to detect lymphatic tissue during image-guided surgery. Further preclinical trials are needed before clinical translation.

Higher Numbers of Examined Lymph Nodes Are Associated with Increased Survival in Resected, Treatment-Naïve, Node-Positive Esophageal, Gastric, Pancreatic, and Colon Cancers

BACKGROUND OR PURPOSE

The role of extended lymphadenectomy as part of resection for lymph node (LN)-positive gastrointestinal (GI) malignancies remains controversial with no clear clinical guidance. The purpose of this retrospective study is to determine whether the number of LNs examined as part of GI malignancy resections affects overall survival (OS) among patients with node-positive esophageal, gastric, pancreatic, and colon cancers.

METHODS

Participants with LN-positive GI cancers who were diagnosed between 2004 and 2015 and underwent oncologic resections were selected from National Cancer Database (NCDB). The primary predictor was the number of examined LNs categorized in tertiles. The effect on OS was measured by hazard ratio (HR) derived from multivariate Cox regression analyses.

RESULTS

From 2004 to 2015, 1877, 10,086, 18,193, and 102,500 patients with LN-positive esophageal, gastric, pancreatic, and colon adenocarcinomas who did not receive neoadjuvant treatment and underwent oncologic tumor resection were registered in the NCDB. Using multivariate Cox proportional hazard modeling, greater LNs examined in surgically resected LN-positive GI cancers were found to be associated with increased OS for all histologies. This association was the strongest (as compared to the lowest tertile) for gastric cancer (middle tertile: HR = 0.91, 95% CI, 0.86-0.96, p = 0.001; highest tertile: HR = 0.73, 95% CI, 0.69-0.78, p < 0.001), followed by colon (highest tertile: HR = 0.86, 95% CI, 0.84-0.88, p < 0.001), esophageal (highest tertile: HR = 0.83, 95% CI, 0.72-0.95, p = 0.01), and pancreatic (highest tertile: HR = 0.93, 95% CI, 0.89-0.98, p = 0.002) cancers.

DISCUSSION AND CONCLUSION

In patients with surgically resected node-positive GI malignancies who did not receive neoadjuvant systemic therapy, a higher number of examined LNs is associated with increased OS. This association is the strongest for gastric cancer, followed by colon, esophageal, and pancreatic cancers respectively.

Definition and reporting of lymphadenectomy and complete mesocolic excision for radical right colectomy: a systematic review

BACKGROUND

Several procedures have been proposed to reduce the rates of recurrence in patients with right-sided colon cancer. Different procedures for a radical right colectomy (RRC), including extended D3 lymphadenectomy, complete mesocolic excision and central vascular ligation have been associated with survival benefits by some authors, but results are inconsistent. The aim of this study was to assess the variability in definition and reporting of RRC, which might be responsible for significant differences in outcome evaluation.

METHODS

PRISMA-compliant systematic literature review to identify the definitions of RRC. Primary aims were to identify surgical steps and different nomenclature for RRC. Secondary aims were description of heterogeneity and overlap among different RRC techniques.

RESULTS

Ninety-nine articles satisfied inclusion criteria. Eight surgical steps were identified and recorded as specific to RRC: Central arterial ligation was described in 100% of the included studies; preservation of mesocolic integrity in 73% and dissection along the SMV plane in 67%. Other surgical steps were inconstantly reported. Six differently named techniques for RRC have been identified. There were 35 definitions for the 6 techniques and 40% of these were used to identify more than one technique.

CONCLUSIONS

The only universally adopted surgical step for RRC is central arterial ligation. There is great heterogeneity and consistent overlap among definitions of all RRC techniques. This is likely to jeopardise the interpretation of the outcomes of studies on the topic. Consistent use of definitions and reporting of procedures are needed to obtain reliable conclusions in future trials. PROSPERO CRD42021241650.

A Clinicopathological Feature-Based Nomogram for Predicting the Likelihood of D3 Lymph Node Metastasis in Right-Sided Colon Cancer Patients

BACKGROUND

Despite advancements in treating right-sided colon cancer patients, the ideal scope of lymphadenectomy remains controversial.

OBJECTIVE

Our objective was to investigate the likelihood of D3 lymph node metastasis in right-sided colon cancer patients and develop a clinicopathological feature-based nomogram for D3 lymphadenectomy.

DESIGN

We retrospectively analyzed 286 right-sided colon cancer patients who underwent D3 lymphadenectomy. The patients were divided into 2 groups based on whether D3 lymph node metastasis was positive. Then, univariable and multivariable logistic regression analyses were performed to obtain independent risk factors for predicting D3 lymph node metastasis. Moreover, we performed receiver operating characteristic curve analyses to evaluate the predictive power of the model.

SETTING

This study was conducted at Nanfang Hospital of Southern Medical University in China.

PATIENTS

A total of 286 consecutive patients who underwent right hemicolectomy and D3 lymphadenectomy as a primary treatment for right-sided colon cancer between January 2016 and December 2019 were enrolled in this study.

MAIN OUTCOME MEASURES

The primary measures were independent risk factors for predicting D3 lymph node metastasis in right-sided colon cancer.

RESULTS

The D3 lymph node metastasis rate in right-sided colon cancer patients was 16.1% (46/286). D3 lymphadenectasis on CT, lymphatic invasion, and T4 tumors were filtered out as independent risk factors for D3 lymph node metastasis according to the multivariable logistic regression analysis. We established a nomogram that predicted D3 lymph node metastasis of right-sided colon cancer on the combination of the 3 factors with an area under the curve of 0.717 (95% CI, 0.629-0.806).

LIMITATIONS

This was a retrospective study from a single center.

CONCLUSIONS

We developed a valuable clinicopathological feature-based nomogram to predict the incidence of D3 lymph node metastasis in right-sided colon cancer patients. Patients with D3 lymphadenectasis on CT, preoperative T4 tumors, and lymphatic invasion should undergo D3 lymphadenectomy. See Video Abstract at http://links.lww.com/DCR/B852 .

UN NOMOGRAMA BASADO EN CARACTERSTICAS CLNICOPATOLGICAS PARA PREDECIR LA PROBABILIDAD DE METSTASIS EN GANGLIOS LINFTICOS D EN PACIENTES CON CNCER DE COLON DERECHO

ANTECEDENTES:A pesar de los avances en el tratamiento de pacientes con cáncer de colon derecho, el ámbito ideal de la linfadenectomía sigue siendo controvertido.OBJETIVO:Investigar la probabilidad de metástasis en los ganglios linfáticos D3 en pacientes con cáncer de colon derecho y desarrollar un nomograma basado en características clínico-patológicas basado para la linfadenectomía D3.DISEÑO:Analizamos retrospectivamente a 286 pacientes con cáncer de colon derecho que se sometieron a linfadenectomía D3. Los pacientes se dividieron en dos grupos en función de si eran positivos para metástasis en los ganglios linfáticos D3. Luego, se realizaron análisis de regresión logística univariable y multivariable para obtener factores de riesgo independientes para predecir metástasis en los ganglios linfáticos D3. Además, realizamos análisis de las curvas de características operatorias del receptor para evaluar el poder predictivo del modelo.SEDE:Este estudio se realizó en el Hospital Nanfang de la Universidad Médica del Sur en China.PACIENTES:Un total de 286 pacientes consecutivos que se sometieron a hemicolectomía derecha y linfadenectomía D3 como tratamiento primario para el cáncer de colon derecho entre enero de 2016 y diciembre de 2019 se inscribieron en este estudio.PRINCIPALES MEDIDAS DE RESULTADO:Las medidas primarias fueron factores de riesgo independientes para predecir las metástasis en ganglios linfáticos D3 en el cáncer de colon derecho.RESULTADOS:La tasa de metástasis en los ganglios linfáticos D3 en pacientes con cáncer de colon del lado derecho fue del 16,1% (46/286). El aumento de tamaño de ganglios D3 en la TC, la invasión linfática y los tumores T4 se filtraron como factores de riesgo independientes de metástasis en los ganglios linfáticos D3 de acuerdo con el análisis de regresión logística multivariable. Establecimos un nomograma que predijo metástasis en los ganglios linfáticos D3 del cáncer de colon derecho en la combinación de los tres factores con un área bajo la curva de 0,717 (IC del 95%, 0,629-0,806).LIMITACIONES:Este fue un estudio retrospectivo de un solo centro.CONCLUSIONES:Desarrollamos un valioso nomograma basado en características clínico-patológicas para predecir la incidencia de metástasis en los ganglios linfáticos D3 en pacientes con cáncer de colon derecho. Los pacientes con crecimiento de ganglios D3 en TC, tumores con clasificación preoperatoria T4 e invasión linfática, deben ser sometidos a linfadenectomía D3. Consulte Video Resumen en http://links.lww.com/DCR/B852 . (Traducción-Dr. Juan Carlos Reyes ).

Computer-Assisted Differentiation between Colon-Mesocolon and Retroperitoneum Using Hyperspectral Imaging (HSI) Technology

Complete mesocolic excision (CME), which involves the adequate resection of the tumor-bearing colonic segment with “en bloc” removal of its mesocolon along embryological fascial planes is associated with superior oncological outcomes. However, CME presents a higher complication rate compared to non-CME resections due to a higher risk of vascular injury. Hyperspectral imaging (HSI) is a contrast-free optical imaging technology, which facilitates the quantitative imaging of physiological tissue parameters and the visualization of anatomical structures. This study evaluates the accuracy of HSI combined with deep learning (DL) to differentiate the colon and its mesenteric tissue from retroperitoneal tissue. In an animal study including 20 pig models, intraoperative hyperspectral images of the sigmoid colon, sigmoid mesentery, and retroperitoneum were recorded. A convolutional neural network (CNN) was trained to distinguish the two tissue classes using HSI data, validated with a leave-one-out cross-validation process. The overall recognition sensitivity of the tissues to be preserved (retroperitoneum) and the tissues to be resected (colon and mesentery) was 79.0 ± 21.0% and 86.0 ± 16.0%, respectively. Automatic classification based on HSI and CNNs is a promising tool to automatically, non-invasively, and objectively differentiate the colon and its mesentery from retroperitoneal tissue.

Complete mesocolic excision in comparison with conventional surgery for right colon cancer: a nationwide multicenter study of the Italian Society of Surgical Oncology colorectal cancer network (CoME-in trial). Study protocol for a randomized controlled trial

Complete mesocolic excision with central vascular ligation, or simply CME, includes the sharp dissection along the mesocolic visceral and parietal layers, with the ligation of the main vessels at their origins. To date, there is low evidence on its safety and efficacy. This is a study-protocol of a multicenter, randomized, superiority trial in patients with right-sided colon cancer. It aims to investigate whether the complete mesocolic excision improves the oncological outcomes as compared with conventional right hemicolectomy, without worsening early outcomes. Data on efficacy and safety of complete mesocolic excision are available only from a large trial recruiting eastern patients and from a low-volume single-center western study. No results on survival are still available. For this reason, complete mesocolic excision continues to be a controversial topic in daily practice, particularly in western world. This new nationwide multicenter large-volume trial aims to provide further data on western patients, concerning both postoperative and survival outcomes.

Pattern of recurrence and survival after D2 right colectomy for cancer: is there place for a routine more extended lymphadenectomy?

BACKGROUND

Conventional Right Colectomy with D2 lymphadenectomy (RC-D2) currently represent the most common surgical treatment of right-sided colon cancer (RCC). However, whether it should be still considered a standard of care, or replaced by a routine more extended D3 lymphadenectomy remains unclear. In the present study, we aim to critically review the patterns of relapse and the survival outcomes obtained from our 11-year experience of RC-D2.

METHODS

Clinical data of 489 patients who underwent RC-D2 for RCC at two centres, from January 2009 to January 2020, were retrospectively reviewed. Patients with synchronous distant metastases and/or widespread nodal involvement at diagnosis were excluded. Post-operative clinical-pathological characteristics and survival outcomes were evaluated including the pattern of disease relapse.

RESULTS

We enrolled a total of 400 patients with information follow-up. Postoperative morbidity was 14%. The median follow-up was 62 months. Cancer recurrence was observed in 55 patients (13.8%). Among them, 40 patients (72.7%) developed systemic metastases, and lymph-node involvement was found in 7 cases (12.8%). None developed isolated central lymph-node metastasis (CLM), in the D3 site. The estimated 3- and 5-year relapse-free survival were 86.1% and 84.4%, respectively. The estimated 3- and 5-year cancer-specific OS were 94.5% and 92.2%, respectively.

CONCLUSIONS

The absence of isolated CLM, as well as the cancer-specific OS reported in our series, support the routine use of RC-D2 for RCC. However, D3 lymphadenectomy may be recommended in selected patients, such as those with pre-operatively known CLM, or with lymph-node metastases close to the origin of the ileocolic vessels.

Oncological and clinical outcomes after conventional right hemicolectomy

PURPOSE

Complete mesocolic excision (CME) has been proposed for better local control of colon cancer and to improve cancer-specific survival (CSS). However, CME may be associated with increased morbidity from bleeding during central vascular ligation. This study aimed to investigate the outcome of conventional right hemicolectomy, a traditional anatomical dissection along anatomical planes with radical excision of the central lymph nodes at the level of the origin of colic artery but without exposure of superior mesenteric vein and artery (SMV/SMA).

METHOD

This was a retrospective review of a cohort of all elective right hemicolectomies performed at a specialist tertiary unit during a five-year period (2011-2015).

RESULTS

Five-hundred-nineteen patients (271 female, a median age of 73.0 years (interquartile range (IQR) 65.0-80.0)) were included (Stage I disease: 2.7%, stage II: 53.2%, stage III: 33.3%, stage IV: 10.8%). At the latest follow-up (a median 47 months (IQR 29-67)), local recurrence occurred in 34 patients (6.6%). Three-year overall survival was 74.4% and 3-year CSS was 85.9%. Subgroup analysis for stage I-III showed local recurrence in 6.0%, sole distant recurrence in 7.6% while 19 patients (4.1%) suffered concomitant local and distant recurrence. The anastomotic leak rate was 1.0% and perioperative bleeding occurred in 1.2%.

CONCLUSIONS

Oncological outcomes comparable to those of CME can be achieved by conventional surgery but with low rates of bleeding complications and anastomotic leakage. The proposed advantages of CME should be carefully considered and balanced against patients' co-morbidities and potential complications.

Right-side colectomy with complete mesocolic excision vs conventional right-side colectomy in the treatment of colon cancer: a systematic review and meta-analysis

BACKGROUND

This meta-analysis aims to investigate the role of complete mesocolic excision (CME) in the treatment of right-side colon cancer when compared with standard right-side hemicolectomy, focusing on oncological outcomes, mortality and morbidity rates.

MATERIALS AND METHODS

A systematic literature search was performed on MEDLINE and EMBASE archives, including studies on CME in right-side colon cancer. Primary outcomes were five-year disease-free survival and five-year overall survival. Secondary outcomes investigated were mortality and morbidity rates, intraoperative blood loss, anastomotic leakage, postoperative ileus, day of postoperative flatus, pulmonary infection, duration of hospital stay and number of lymph nodes harvested.

RESULTS

Seventeen studies have been included in this meta-analysis for a total of 3918 patients. The five-year disease-free survival (DFS) and overall survival (OS) results improved in the CME group with respect to conventional right-side colectomy with an OR 1.88 (95% CI 1.02-3.45) and OR 2.77 (95% CI 1.33-5.74), respectively. The incidence of mortality and morbidity was comparable between the two groups. Moreover, conventional surgery time was faster than CME (MD 33.69 min, 95% CI 12.79-54.59), while no significant differences were reported in mean blood loss and hospital stay. Furthermore, the CME group showed a higher mean number of harvested lymph nodes (MD 7.08 lymph nodes 95% CI 4.90-9.27).

CONCLUSION

Complete mesocolic excision of the right-side colectomy improves oncological outcomes without increasing mortality and morbidity rates compared to standard right-side hemicolectomy. CME should therefore be routinely performed in the treatment of right-side colon cancer.

The Value of Sentinel Lymph Node Mapping for the Staging of Node-Negative Colon Cancer: Propensity Score and Mediation Analyses

Objectives

Mediation analysis to assess the protective impact of sentinel lymph node (SLN) mapping on prognosis and survival of patients with colon cancer through a more precise evaluation of the lymph node (LN) status.

Background

Up to 20% of patients with node-negative colon cancer develop disease recurrence. Conventional histopathological LN examination may be limited in describing the real metastatic burden of LN.

Methods

Data of 312 patients with stage I & II colon cancer was collected prospectively. Patients were either staged using intraoperative SLN mapping with multilevel sectioning and immunohistochemical staining of the SLN or conventional techniques. The value of the SLN mapping for the detection of truly node-negative patients was assessed using Cox regression and mediation analysis.

Results

SLN mapping was performed in 143 patients. Disease recurrence was observed in 13 (9.1%) patients staged with SLN mapping and in 27 (16%) staged conventionally. Five-year overall survival (OS) rate was 82.7% (95% confidence interval [CI], 76.5-89.4%) with SLN mapping compared with 65.8% (95% CI, 58.8-73.7%). Five-year cancer-specific survival (CSS) was 95.1% (95% CI, 91.3-99.0%) with SLN mapping compared with 92.5% (95% CI, 88.0-97.2%). Node-negative staging with SLN mapping was associated with significantly better OS (hazard ratio [HR], 0.64; 95% CI, 0.56-0.72; P < 0.001) and CSS (HR, 0.49; 95% CI, 0.39-0.61; P < 0.001) in multivariate analysis. Mediation analysis confirmed a direct protective effect of SLN mapping on OS (HR, 0.78; 95% CI, 0.52-0.96; P < 0.01) and disease-free survival (DFS) (HR, 0.75; 95% CI, 0.48-0.89; P < 0.01).

Conclusions

Staging performed by SLN mapping with multilevel sectioning provides more accurate results than conventional staging. The observed clinically relevant and statistically significant benefit in OS and DFS is explained by a more accurate detection of positive LN by SLN mapping.

Feasibility and Safety of Laparoscopic Complete Mesocolic Excision (CME) for Right-sided Colon Cancer: Short-term Outcomes. A Randomized Clinical Study

OBJECTIVE

The aim of this prospective clinical study is to compare short-term outcome of laparoscopic right hemicolectomy using the Complete Mesocolic Excision (CME group) with patients who underwent conventional right-sided colonic resection (NCME group).

SUMMARY BACKGROUND DATA

Although CME with central vascular ligation in laparoscopic right hemicolectomy is associated with a significant decrease in local recurrence rates and improvements in cancer-related 5-year survival, there may be additional risks associated with this technique because of increased surgical complications. As a result, there is controversy surrounding its use.

METHODS

In this randomized controlled trial, several primary endpoints (operative time, intraoperative blood loss, other complications, conversion rate, and anastomotic leak) and secondary endpoints (overall postoperative complications) were evaluated. In addition, we evaluated histopathologic data, including specimen length and the number of lymph nodes harvested, as objective signs of the quality of CME, related to oncological outcomes.

RESULTS

The CME group had a significantly longer mean operative time than the NCME group (216.3 minutes vs 191.5 minutes, P = 0.005). However, the CME group had a higher number of lymph nodes (23.8 vs 16.6; P < 0.001) and larger surgical specimens (34.3 cm vs 29.3 cm; P = 0.002). No differences were reported with respect to intraoperative blood loss, conversion rate, leakage, or other postoperative complications.

CONCLUSIONS

In this study laparoscopic CME were a safe and feasible technique with improvement in lymph nodes harvesting and length of surgical specimens with no increase of surgical intraoperative and postoperative complications.

Central vascular ligation and mesentery based abdominal surgery

In the nineteenth century the idea of a correct surgical approach in oncologic surgery moved towards a good lymphadenectomy. In colon cancer the segment is removed with adjacent mesentery, in gastric cancer or pancreatic cancer a good oncologic resection is obtained with adequate lymphadenectomy. Many guidelines propose a minimal lymph node count that the surgeon must obtain. Therefore, it is essential to understand the adequate extent of lymphadenectomy to be performed in cancer surgery. In this review of the current literature, the focus is on "central vascular ligation", understood as radical lymphadenectomy in upper and lower gastrointestinal cancer, the evolution of this approach during the years and the improvement of laparoscopic techniques. For what concerns laparoscopic surgery, the main goal is to minimize post-operative trauma introducing the "less is more" concept whilst preserving attention for oncological outcomes. This review will demonstrate the importance of a scientifically based standardization of oncologic gastrointestinal surgery, especially in relation to the expansion of minimally invasive surgery and underlines the importance to further investigate through new randomized trials the role of extended lymphadenectomy in the new era of a multimodal approach, and most importantly, an era where minimally invasive techniques and the idea of "less is more" are becoming the standard thought for the surgical approach.

Complete mesocolic excision versus conventional surgery for colon cancer: A systematic review and meta-analysis

AIM

Complete mesocolic excision (CME) lacks consistent data advocating operative superiority compared to conventional surgery for colon cancer. We performed a systematic review and meta-analysis, analysing population characteristics and perioperative, pathological and oncological outcomes.

METHODS

D3 extended lymphadenectomy dissection was considered comparable to CME, and D2 and D1 dissection to be comparable to conventional surgery. Outcomes reviewed included lymph node yield, R1 resection, overall complications, overall survival and disease-free survival.

RESULTS

In all, 3039 citations were identified; 148 studies underwent full-text reviews and 31 matched inclusion criteria: total cohort 26 640 patients (13 830 CME/D3 vs. 12 810 conventional). Overall 3- and 5-year survival was higher in the CME/D3 group compared with conventional surgery: relative risk (RR) 0.69 (95% CI 0.51-0.93, P = 0.016) and RR 0.78 (95% CI 0.64-0.95, P = 0.011) respectively. Five-year disease-free survival also demonstrated CME/D3 superiority (RR 0.67, 95% CI 0.52-0.86, P < 0.001), with similar findings at 1 and 3 years. There were no statistically significant differences between the CME/D3 and conventional group in overall complications (RR 1.06, 95% CI 0.97-1.14, P = 0.483) or anastomotic leak (RR 1.02, 95% CI 0.81-1.29, P = 0.647).

CONCLUSIONS

Meta-analysis suggests CME/D3 may have a better overall and disease-free survival compared to conventional surgery, with no difference in perioperative complications. Quality of evidence regarding survival is low, and randomized control trials are required to strengthen the evidence base.

2D vs 3D laparoscopic right colectomy: A propensity score-matching comparison of personal experience with systematic review and meta-analysis

BACKGROUND

The benefits of laparoscopic approach for right colectomy have been well established. However, the technical difficulty to construct the intra-corporeal anastomosis is still cumbersome.

AIM

To analyze the results of 3D and 2D laparoscopic right colectomy and to compare it to the published series through a systematic review and meta-analysis.

METHODS

A retrospective study with propensity score matching analysis of patients undergoing laparoscopic right colectomy at Umbria2 Hospitals from January 2014 to March 2020 was performed. A systematic review was accomplished comparing 2D and 3D right colectomy.

RESULTS

In the personal series 47 patients of the 2D group were matched to 47 patients of the 3D group. The 3D group showed a favorable trend in terms of mean operative time (170.7 ± 32.9 min vs 183.8 ± 35.4 min; P = 0.053) and a significant lower anastomotic time (16.9 ± 2.3 min vs 19.6 ± 2.9 min, P < 0.001). The complete mesocolic excision (CME) subgroups analysis showed a shorter anastomotic time (16.5 ± 1.8 min vs 19.9 ± 3.0 min; P < 0.001) and operative time (175.0 ± 38.5 min vs 193.7 ± 37.1 min; P = 0.063) in the 3D group. Six studies and our series were included in the meta-analysis with 551 patients (2D group: 291; 3D group: 260).The pooled analysis demonstrated a significant difference in favour of the 3D group regarding the operative time (P < 0.001) and the anastomotic time (P < 0.001) while no differences were identified between groups in terms of blood loss (P = 0.827), LNH yield (P = 0.243), time to first flatus (P = 0.333), postoperative complications (P = 0.718) and length of stay (P = 0.835).

CONCLUSION

The meta-analysis results showed that 3D laparoscopic right colectomy shortens operative and anastomotic time without affecting the standard lymphadenectomy. In our series, the advantage of the 3D system becomes evident when CME and/or more complex associated procedure are requested significantly reducing both the total operative and the anastomotic time.

Qualitative umbrella review of systematic reviews on complete mesocolic excision for colon cancer

BACKGROUND

Complete mesocolic excision (CME) of colon cancer with extended lymphadenectomy was suggested to improve radical resection of colon cancer. This comprehensive review aimed to assess the current literature for the outcomes of CME of colon cancer through an appraisal of the findings of published systematic reviews and meta-analyses.

METHODS

A systematic literature review searching for the studies that assessed the outcome of CME of colon cancer was conducted. Electronic databases were queried from 2009 through November 2020. The main objectives of this review were to illustrate the technical aspects and outcome of CME and to summarize the findings of the published systematic reviews.

RESULTS

Thirteen systematic reviews were retrieved. All reviews found CME to provide longer bowel, larger area of mesentery resected, and more lymph nodes (LNs) retrieved than standard colectomy. All systematic reviews except two found similar complication rates between CME and standard colectomy. Four systematic reviews documented the survival benefit of CME in regards to improved overall and disease-free survival. Using the laparoscopic approach for CME did not compromise the oncologic outcomes of the procedures, yet was associated with less intraoperative blood loss, faster recovery, and potential survival benefits.

CONCLUSIONS

CME is associated with better specimen quality, more LNs clearance, and potential survival benefits compared to standard colectomy. However, the lack of robust data from well-designed multicenter randomized trials may prevent drawing firm conclusions on the oncologic benefits of CME. Further high-quality studies are needed before recommending CME as the standard of care for colon cancer.

Complete mesocolic excision and D3 lymphadenectomy with central vascular ligation in right-sided colon cancer: a systematic review of postoperative outcomes, tumor recurrence and overall survival

BACKGROUND

In right-sided colon cancer surgery, currently there is a great deal of discussion and debate regarding complete mesocolic excision (CME) versus conventional right hemicolectomy (CRH) on postoperative outcomes and oncological results. Our aim was to perform a systematic review of the short- and long-term outcomes of CME to standardize surgical approach in patients with right-sided colon cancer.

METHODS

A systematic review was performed examining available data on randomized and non-randomized studies evaluating the role of CME and D3 lymphadenectomy in the treatment of right-sided colon cancer, in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) standards.

RESULTS

After literature search, 919 studies have been recorded, 110 studies underwent full-text reviews and 30 studies met inclusion criteria. The total number of CME procedures was 5931. Postoperative complications was reported in 28 studies with pooled overall complications of 1.88% for CME surgery. Six studies reported 0% of overall postoperative complications and they demonstrated a low incidence of complications following CME procedure. Anastomotic leak was reported in 27 studies with pooled proportion of 0.92% after CME resections. There were 16 papers reporting overall survival following CME procedure, with a mean of 85% of patients survived at 5 years. Mean 5-year overall survival was 93.05% in stage I patients, 89.76% in stage II patients and 79.65% in stage III patients. Local and distant recurrence were included in 21 studies, reporting tumor recurrence rate of 12.25% following CME. 5-year tumor recurrence was 5.8% in stage I patients, 7.68% in stage II patients and 15.69% in stage III patients.

CONCLUSIONS

CME does not increase the risk of postoperative complications and significantly improves the long-term oncological impact. Prospective multicentre studies results are needed to verify if CME could be considered standard surgery for right colon cancer.

Robotic complete mesocolic excision versus conventional robotic right colectomy for right-sided colon cancer: a comparative study of perioperative outcomes

AIM

This study aims to compare the short-term outcomes of robotic complete mesocolic excision (RCME) versus conventional robotic right colectomy (RRC) for right-sided colon cancer.

METHODS

Consecutive patients who underwent robotic surgery for right-sided colon cancer in a public quaternary and a private tertiary healthcare centre between November 2018 and June 2020 were included. Clinical, perioperative and histopathological variables were collected and analysed.

RESULTS

Fifty-one patients were included; 25 (49%) of them had an RCME. The groups were evenly distributed in terms of demographic characteristics and tumour location. Operative time was similar between both groups, and no patients required conversion to open surgery. There were no differences in overall complications (16% in RCME vs. 26.9% in RRC; p = 0.499) or their profile between groups. There were no anastomotic leaks recorded, and the reoperation rates were similar (0% for RCME versus 3.8% for RRC; p = 1). In addition, the median length of hospital stay was similar in between the RCME and the RRC groups (4 [4-6] days versus 5 [3-8.5] days, respectively; p = 0.891). Whilst there were no differences in the TNM staging, the mean number of lymph nodes harvested with RCME was 37.7 (±12.9) compared to 21.8 (±7.5) with RCC (p < 0.001).

CONCLUSION

In our series, RCME was associated with a higher lymph node harvest and a similar morbidity profile compared to RCC. Further studies are required to validate these results and provide long-term oncologic outcomes.

Laparoscopic Colectomy vs Laparoscopic CME: a Retrospective Study of Two Hospitals with Comparable Laparoscopic Experience

PURPOSE

To compare laparoscopic non-CME colectomy with laparoscopic CME colectomy in two hospitals with similar experience in laparoscopic colorectal surgery.

METHODS

Data was collected retrospectively from Päijät-Häme Central Hospital (PHCH, NCME group) and Central Finland Central Hospital (CFCH, CME group) records. Elective laparoscopic resections performed during 2007-2016 for UICC stage I-III adenocarcinoma were included to assess differences in short-term outcome and survival.

RESULTS

There were 340 patients in the NCME group and 325 patients in the CME group. CME delivered longer specimens (p < 0.001), wider resection margins (p < 0.001), and more lymph nodes (p < 0.001) but did not result in better 5-year overall or cancer-specific survival (NCME 77.9% vs CME 72.9%, p = 0.528, NCME 93.2% vs CME 88.9%, p = 0.132, respectively). Thirty-day morbidity, mortality, and length of hospital stay were similar between the groups. Conversion to open surgery was associated with decreased survival.

DISCUSSION

Complete mesocolic excision (CME) is reported to improve survival. Most previous studies have compared open CME with open non-CME (NCME) or open CME with laparoscopic CME. NCME populations have been historical or heterogeneous, potentially causing bias in the interpretation of results. Studies comparing laparoscopic CME with laparoscopic NCME are few and involve only small numbers of patients. In this study, diligently performed laparoscopic non-CME D2 resection delivered disease-free survival results comparable with laparoscopic CME but was not safer.

A global systematic review and meta-analysis on laparoscopic vs open right hemicolectomy with complete mesocolic excision

PURPOSE

The aim of this study was to compare the outcomes of right hemicolectomy with CME performed with laparoscopic and open surgery.

METHODS

PubMed, Scopus, Web of Science, China National Knowledge Infrastructure, Wanfang Data, Google Scholar and the ClinicalTrials.gov register were searched. Primary outcome was the overall number of harvested lymph nodes. Secondary outcomes were short and long-term course variables. A meta-analysis was performed to calculate risk ratios.

RESULTS

Twenty-one studies were identified with 5038 patients enrolled. The difference in number of harvested lymph nodes was not statistically significant (MD 0.68, - 0.41-1.76, P = 0.22). The only RCT shows a significant advantage in favour of laparoscopy (MD 3.30, 95% CI - 0.20-6.40, P = 0.04). The analysis of CCTs showed an advantage in favour of the laparoscopic group, but the result was not statically significantly (MD - 0.55, 95% CI - 0.57-1.67, P = 0.33). The overall incidence of local recurrence was not different between the groups, while systemic recurrence at 5 years was lower in laparoscopic group. Laparoscopy showed better short-term outcomes including overall complications, lower estimated blood loss, lower wound infections and shorter hospital stay, despite a longer operative time. The rate of anastomotic and chyle leak was similar in the two groups.

CONCLUSIONS

Despite the several limitations of this study, we found that the median number of lymph node harvested in the laparoscopic group is not different compared to open surgery. Laparoscopy was associated with a lower incidence of systemic recurrence.

Complete mesocolic excision in minimally invasive surgery of colonic cancer: do we need the robot?

Background

Robotic surgery offers favorable prerequisites for complex minimally invasive surgeries which are delivered by higher degrees of freedom, improved instrument stability, and a perfect visualization in 3D which is fully surgeon controlled. In this article we aim to assess its impact on complete mesocolic excision (CME) in colon cancer and to answer the question of whether the current evidence expresses a need for robotic surgery for this indication.

Methods

Retrospective analysis and review of the current literature on complete mesocolic excision for colon cancer comparing the outcome after open, laparoscopic, and robotic approaches.

Results

Complete mesocolic excision results in improved disease-free survival and reduced local recurrence, but turns out to be complex and prone to complications. Introduced in open surgery, the transfer to minimally invasive surgery resulted in comparable results, however, with high conversion rates. In comparison, robotic surgery shows a reduced conversion rate and a tendency toward higher lymph node yield. Data, however, are insufficient and no high-quality studies have been published to date. Almost no oncologic follow-up data are available in the literature.

Conclusion

The current data do not allow for a reliable conclusion on the need of robotic surgery for CME, but show results which hypothesize an equivalence if not superiority to laparoscopy. Due to recently published technical improvements for robotic CME and supplementary features of this method, we suppose that this approach will gain in importance in the future.

Comparing complete mesocolic excision versus conventional colectomy for colon cancer: A systematic review and meta-analysis

Conventional colectomy, and the Japanese Society for Cancer of the Colon and Rectum (JSCCR) D2 Lymphadenectomy (LND2), are currently considered standard of care for surgical management of colon cancer. Colectomy with complete mesocolic excision (CME) and JSCCR D3 Lymphadenectomy (LND3) are more radical alternative approaches and provide a greater degree of lymph nodal clearance. However, controversy exists over the long-term benefits of CME/LND3 over non-CME colectomies (NCME)/LND2. In this study, we performed a systematic review and meta-analysis to compare the surgical, pathological, and oncological outcomes of CME/LND3 with NCME/LND2. Embase, Medline and CENTRAL databases were searched from inception until May 15, 2020, in accordance with PRISMA guidelines. Studies were included if they compared curative intent CME/LND3 with NCME/LND2. Weighted mean differences (WMD) and odds ratios (OR) were estimated for continuous and dichotomous outcomes respectively. Out of 1310 unique citations, 106 underwent full-text review, and 30 were included for analysis. In total, 21,695 patients underwent resection for colon cancer. 11,625 received CME/LND3, and 10,070 underwent NCME/LND2. No significant differences were found in post-operative morbidity and mortality. Both overall and disease-free survival favored CME/LND3 (5-year OS: OR = 1.29; 95% CI 1.02 to 1.64, p = 0.03; 5-year DFS: OR = 1.61; 95% CI 1.14 to 2.28; p = 0.007). This is the first systematic review and meta-analysis to demonstrate that CME/LND3 has superior long-term survival outcomes compared to NCME/LND2.

Early stage colon cancer: Current treatment standards, evolving paradigms, and future directions

Colon cancer continues to be one of the leading causes of mortality and morbidity throughout the world despite the availability of reliable screening tools and effective therapies. The majority of patients with colon cancer are diagnosed at an early stage (stages I to III), which provides an opportunity for cure. The current treatment paradigm of early stage colon cancer consists of surgery followed by adjuvant chemotherapy in a select group of patients, which is directed at the eradication of minimal residual disease to achieve a cure. Surgery alone is curative for the vast majority of colon cancer patients. Currently, surgery and adjuvant chemotherapy can achieve long term survival in about two-thirds of colon cancer patients with nodal involvement. Adjuvant chemotherapy is recommended for all patients with stage III colon cancer, while the benefit in stage II patients is not unequivocally established despite several large clinical trials. Contemporary research in early stage colon cancer is focused on minimally invasive surgical techniques, strategies to limit treatment-related toxicities, precise patient selection for adjuvant therapy, utilization of molecular and clinicopathologic information to personalize therapy and exploration of new therapies exploiting the evolving knowledge of tumor biology. In this review, we will discuss the current standard treatment, evolving treatment paradigms, and the emerging biomarkers, that will likely help improve patient selection and personalization of therapy leading to superior outcomes.

Robotic complete mesocolic excision and central vascular ligation for right-sided colon cancer: short-term outcomes from a case series

BACKGROUND

Despite conflicting data regarding oncological outcomes, studies demonstrate that complete mesocolic excision (CME) and central vascular ligation (CVL) for right-sided colon cancer removes significantly more tissue and yields higher lymph node counts when compared to conventional resection. This study aims to report the safety profile of CME and CVL in patients undergoing robotic surgery for right-sided colon cancer during the introduction of this technique across two institutions.

METHODS

Patients who underwent an elective robotic right colectomy with CME and CVL for right-sided colon cancer in a public quaternary and a private tertiary healthcare centre between November 2018 and April 2020 were included. Demographic, clinical, perioperative and histopathological variables were recorded and analysed.

RESULTS

Twenty patients (13 females) with a median age of 69 (23-83) years and median body mass index of 27 (19-46) were included. All of them had a pre-operative diagnosis of right-sided colon adenocarcinoma. Median operative time and blood loss were 140 (130-300) min and 30 (20-100) mL, respectively. There were no conversions or intra-operative complications. There were two post-operative complications recorded (one ileus and one intra-abdominal collection treated with intravenous antibiotics) and no re-interventions. Median length of stay was 4 (2-8) days. All patients had an R0 resection, and the median lymph node yield was 36 (22-80) lymph nodes.

CONCLUSION

This series demonstrates a safe introduction of robotic CME and CVL in patients with right-sided colon cancer. The lymph node harvest obtained with CME and CVL in this setting was high.

Surgical management of recurrent colon cancer

There have been significant developments in the management of advanced and recurrent colorectal cancer in recent decades. 70% of primary colorectal tumours arise in the colon and for patients with stage I-III disease, the standard of care is surgical resection followed by adjuvant therapy where appropriate. Locoregional recurrence (LR) occurs in 4-11.5% of patients following treatment of primary colon cancer with curative intent, and can be categorised as peri-anastomotic, mesenteric/paracolic (nodal), retroperitoneal and peritoneal. Of these, peritoneal recurrence is usually recognised as the most challenging type of recurrence to manage. Patients with isolated peri-anastomotic or limited nodal recurrence in the mesentery or retroperitoneum may be curable by radical salvage surgery, which often requires en bloc multi-visceral resection, while patients with low volume peritoneal metastases may be candidates for cytoreductive surgery with hyperthermic intraperitoneal chemotherapy. Ensuring complete resection along embryonic mesocolic planes or en bloc resection of contiguously involved structures are best strategies to reduce the likelihood of local recurrence through a R1 resection margin. The role of complete mesocolic excision (CME) with high vascular ligation has been demonstrated to increase nodal yield and improve overall survival although this is more contentious. In patients with T4a disease and serosal surface involvement, peritoneal recurrence represents the greatest threat. Efforts for early diagnosis of peritoneal recurrence in these patients or prophylactic treatment, while intuitive have not demonstrated the survival benefit that would be expected. Other than locoregional recurrence (LR), systemic recurrence may occur in up to 50% of patients who have undergone curative resection for colorectal cancer. In keeping with portal venous outflow, the most common site of systemic recurrence is the liver. Although previously thought to be a fatal condition, liver resection is now the standard of care where liver metastases can be completely resected with clear margins plus leaving an adequate liver remnant with intact vascular inflow, outflow and biliary drainage. This can usually be achieved in 26-45% of patients presenting with liver metastases. Liver surgeons at the forefront of liver resection have also developed techniques to induce liver hypertrophy so as to improve likelihood of resectability. Even where patients have non-resectable disease, ablative techniques have become increasingly common. Naturally, none of these would be possible without the advent of improved chemotherapeutic and biological options in the field of medical oncology. Pulmonary metastasectomy with curative intent may be possible in a small number (10%) of patients with lung metastases, which is associated with an overall survival of up to 40%. Unlike liver metastases, proportionally less patients with pulmonary metastases will be resectable. For these patients, several ablative options are available. For all patients with recurrent colon cancer, patient selection for radical salvage surgery and decisions surrounding treatment strategy (including use of systemic therapy or ablative procedures) should take place in a multidisciplinary team setting.

Colorectal cancer treated by resection and extended lymphadenectomy: patterns of spread in left- and right-sided tumours

BACKGROUND

Whether tumour side affects the anatomical extent and distribution of lymph node metastasis in colon cancer is unknown. The impact of tumour side on the anatomical pattern of lymphatic spread in colon cancer was assessed.

METHODS

Patients with stage III colon cancer from a Japanese multi-institutional database who underwent extensive (D3) lymphadenectomy, which is similar in concept to complete mesocolic excision with central venous ligation, were divided into groups with right- and left-sided tumours. Based on location, mesenteric lymph nodes were categorized as paracolic (L1), intermediate (L2) or central (L3). The Kaplan-Meier method was used to evaluate disease-free survival (DFS) and overall survival (OS), and multivariable Cox models were used to evaluate the association between anatomical lymph node level, metastatic pattern and outcome.

RESULTS

A total of 4034 patients with stage III colon cancer (right 1618, left 2416) were included. Unadjusted OS was worse in patients with right colon cancer (hazard ratio 1·23, 95 per cent c.i. 1·08 to 1·40; P = 0·002), but DFS was similar. Right-sided tumours more frequently invaded L3 nodes than left-sided lesions (8·5 versus 3·7 per cent; P < 0·001). The proportion of patients with a skipped pattern of lymphatic spread was higher in right than in left colon cancer (13·7 versus 9·0 per cent; P < 0·001). In multivariable analysis, invasion of L3 nodes was associated with worse OS in left but not in right colon cancer. The presence of skipped metastasis was associated with worse DFS in left, but not right, colon cancer.

CONCLUSION

There are significant differences in the pattern of lymph node invasion between right- and left-sided stage III colon cancer, and in their prognostic significance, suggesting that tumour side may dictate the operative approach.

Robotic versus laparoscopic right colectomy within a systematic ERAS protocol: a propensity-weighted analysis

The purpose of this study is to compare the early postoperative and pathological outcomes of robotic right colectomy (RRC) to those of laparoscopic right colectomy (LRC) with intracorporeal anastomosis (IA) within the systematic application of an enhanced recovery after surgery (ERAS) program. A single-institution prospective database of patients who underwent elective RRC or LRC with IA for neoplastic lesions between April 2010 and June 2018 was retrospectively reviewed. The patients' demographic characteristics, and perioperative and pathological outcomes were analyzed. Propensity-weighted analysis was employed to address potential selection biases of treatment allocation. A total of 216 patients (46 RRC, 170 LRC) were included. RRC demonstrated a significantly longer operative time (mean 242.43 min, SD 47.51) compared to LRC (mean 187.60 min, SD 56.60) (p = 0.001), confirmed by the propensity-weighted analysis (Coefficient 50.65; p < 0.001). Conversion rate between the two groups was comparable (p = 0.99). Median length of hospital stay (LOS) was the same in the RRC and the LRC group (4 days, p = 0.35). Readmission rate within 30 days in the RRC and LRC group was 2.2% and 2.4%, respectively (p = 0.99). Overall 30-day morbidity and 30-day mortality was 32.6% versus 27.1% (p = 0.46), and 0% versus 1.2% (p = 0.99) in the robotic and laparoscopic groups, respectively. No difference was found in the number of harvested lymph nodes (p = 0.75). In an ERAS environment, without the bias of mixed techniques of anastomosis, RRC had similar postoperative and pathological outcomes compared to the laparoscopic approach, but was associated with a longer operative time.

Complete mesocolic excision for colon cancer: is it worth it?

Total mesorectal excision (TME) has been the miracle surgical technique which has since allowed the outcomes of rectal cancer to surpass that of colon cancer. Complete mesocolic excision (CME) attempts to adopt the same principles as that of TME and apply it to colon cancer surgery. Initial retrospective case series and comparative studies have shown promising oncological outcomes. CME entails the en bloc removal of a sufficient length of colonic specimen within an intact peritoneal envelop with extended lymphadenectomy through a high central ligation of vessels. This technique, standardizing the method for resection of right sided colon cancer, has witness promising perioperative and oncological data for both open and laparoscopic methods. However, most data available are mostly retrospective with a glaring lack of level 1 evidence. Despite the technique showing similar outcomes to that of conventional colectomy, parts of the procedure put the patient (and surgeon) at risk of potentially catastrophic complications. As promising as the initial results of CME has been, more well-designed randomized control trials are necessary to justify the increased risks taken and effort to mount the learning curve for CME.

Prognostic significance of number versus location of positive mesenteric nodes in stage iii colon cancer

INTRODUCTION

Debate persists on the ideal extent of lymphadenectomy for colon cancer (CC). Specifically, it is unknown whether the anatomical location of positive lymph nodes (LN) has any independent prognostic significance. We assessed the prognostic value of positive LN location in stage III CC patients who underwent extensive (D3) lymphadenectomy.

METHODS

Patients from Kanagawa Cancer Center, Japan, who underwent D3 dissection for CC from 2000 to 16 were analyzed. Mesenteric LN were classified according to location as paracolic (L1), intermediate (L2), or central (L3). Recurrence-free survival (RFS) and the corresponding hazard function were evaluated with their trends over the L groups. Multivariate Cox models were used to evaluate the association of LN location with RFS.

RESULTS

Four hundred forty-six stage III patients were analyzed. The mean number of examined/positive nodes per patient was 42.5/2.6 in L1 (n = 310), 40.9/4.8 in L2 (n = 111), and 44.0/9.8 in L3 (n = 25). RFS was worse for L3 vs. L2 (HR: 2.00, 95%CI [1.05-3.75], p = 0.034) and for L3 vs. L1 (2.62 [1.45-4.71], p = 0.001), but not significantly different between L2 and L1 (1.32 [0.89-1.5], p = 0.17). In a multivariate model adjusting for age, tumor size, and number of lymph nodes harvested T-stage (p < 0.001), adjuvant therapy (p < 0.0038), lymphatic invasion (p = 0.023), and LNR (p = 0.038) were significantly associated with RFS, but not L level or tumor location.

CONCLUSION

The anatomical location of invaded LN does not significantly correlate with RFS in CC, after adjusting for potential confounders. Central LN are infrequently invaded and confer a worse RFS.

Biology-Based Surgery: The Extent of Lymphadenectomy in Cancer of the Colon

The progression of colon cancer (CC) involves hematogenous and lymphatic spread to locoregional lymph nodes (LN), distant LN, and metastatic sites including the liver. The biological mechanisms that govern CC progression remain elusive. The Halsted model assumes an orderly, stepwise progression from the primary tumor to nearby nodes, henceforth to anatomically more distant nodes, and ultimately to distant organs. The Fisher model, on the other hand, regards the release of metastatic cells as early and essentially random events. The underlying biology has important implications for the ideal extent of surgery: when the Fisher model is correct, efforts to remove apical (central), extramesenteric, or para-aortic LN are unlikely to affect the oncological outcome. Recent data from phylogenetic studies suggest that cancer cell populations differ genetically among different LN stations and from distant metastases. Circulating tumor cells and other liquid biomarkers can be detected in the circulation of patients with early-stage disease. Local recurrence in CC is uncommon, and it is associated with a high risk of systemic progression and poor survival. Clinical studies comparing standard colectomy with extensive surgery (high ligation of the inferior mesenteric artery, complete mesocolic excision, D3 dissection, and para-aortic or extramesenteric node dissection) show that these techniques increase the LN count, while any beneficial effect on the risk of local recurrence or disease-free survival is at present uncertain due to the lack of controlled trials. Ongoing randomized trials comparing extensive vs. standard surgery for CC will generate important answers.